There is a need to improve the interconnectivity between the photonics domain and the electronics domain in order to effectively integrate multi-functional photonic/electronic systems. However, the mismatch in physical scaling between photonic components and electronic components presents a significant challenge to the high density integration of photonics and silicon-compatible optoelectronics. One of the most challenging technical barriers to the development of photonics on silicon is the lack of a practical silicon-integrated light source which is (a) highly efficient; (b) ultra-compact; (c) electrically controllable; (d) CMOS process/integration compatible; and (e) reliable.
Vertical-cavity light emitting sources, including light emitting diodes and lasers could be ideal compact light sources for large-scale silicon-based photonics if they could be directly built on a silicon wafer because vertical cavity light emitting sources: (1) can be wafer-scale fabricated and probed; (2) can be fabricated in high-density 2D arrays; and (3) have low diffraction output beams for efficient coupling. However, conventional vertical-cavity light emitting source technology utilizes thick distributed-Bragg reflector (DBR) mirrors which limit the device performance and integration density.